Background: Few studies have assessed the effect of multiple health conditions among patients with heart disease, particularly the economic implications of having multiple conditions. Methods and Results: This study used a microsimulation model, HealthWealthMOD, to assess the effect of comorbidities on the labor force participation of 45-64-year-old Australians with heart disease, and the indirect economic costs to these individuals and government. For most comorbid conditions, there is a significant increase in the chance of an individual being out of the labor force, relative to those with heart disease alone. For example, individuals with heart disease and arthritis have more than 6-fold the odds of being out of the labor force relative to those with heart disease alone (OR 6.64, 95% CI: 2.46-17.95). People with heart disease and =1 comorbidities also receive a significantly lower income, pay less in taxation and receive more in government transfer payments than those with heart disease alone. Conclusions: It is important to consider whether an individual with heart disease also has other health conditions, as individuals with comorbidities have inferior financial situations and are a greater burden on government finances than those with only heart disease.